Find us in WORKSHOP Magazine this month for a little insight to how AW MotorSport began and our goal to provide a good quality service for Porsche owners and many other brands
As much as we love Porsche 911s, it’s nice to work on something different from time to time, and they don’t come much more different than this Porsche 928 S4 from the late 1980s.
The Porsche 928 was launched back in 1977 and, with its space age lines, must have looked super modern in those days of boxy Ford Cortinas. It’s still an eye-catching car today! Porsche originally intended the 928 to replace the ageing 911 but the rear-engined classic refused to die and, try as it might, the modern upstart failed to usurp the mighty 911.
However, that’s not to say the Porsche 928 was a bad car – far from it. With its tempting mix of front-mounted V8 power and two-plus-two accommodation, the 928 was a formidable grand-tourer, capable of devouring continents with ease. It remained in production until 1992.
This example is with us for a recommissioning and a light restoration. More photos to follow!
There’s an interesting article on MSN Cars about a barn full of classic Porsche 356s and 911s.
Around 200 cars are in the collection and are being auctioned. MSN is gushing about the cars and we can see why. However, let’s be rational about this. Judging from the photos many of the Porsches are in very poor condition, with rusty bodyshells, scruffy interiors and some appear to be incomplete.
Now restoring a Porsche is very expensive – budget for around £60,000 for a full and proper restoration of a classic 911 or 356. And that’s the same whether it’s a rare and valuable 2.7RS, for instance, or a rather more affordable 911SC. So think carefully before buying a restoration project.
Like the Beetle’s, a Porsche 911 engine is removed from below, and that stands true for all models, from 1963 to 2012, plus Boxsters and Caymans.
In many ways, it’s easier than hoisting an engine upwards through the bonnet, which is the case on most cars. You just need to have the car high enough off the ground and the engine drops right out. The exhaust system stays on the engine, too, which saves messing around disconnecting rusty and inaccessible fittings.
OK, it’s not quite that simple. On modern Porsches, such as this 997, there’s a fair bit of work involved in disconnecting the various pipes and cables from the engine (air-cooled cars had an advantage here as they had no water pipes!). We allow four hours to get an engine out, and about the same to put it back again.
It’s good that it’s straightforward to drop a Porsche 911 engine, as you need to do so for various jobs on the car. In this case, the engine had to come out simply to renew some air-conditioning pipes.
Look at how large a modern Porsche 911 engine is when it’s out of the car. Of course, much of that is the exhaust system but it’s still a chunky unit.
Over the years, an air of mystery has developed over the Porsche 911’s heating system. However, in its early form, at least, it’s a fairly simple system – certainly less complex than some water-based ones.
If your 911’s cabin isn’t getting warm, the first things to check are the heat exchangers and the rear-mounted heater valves (on pre-1989 cars only) in front of them.
Let’s start with the valves. These mild-steel items are located on the underside of the car so are exposed to moisture from the road. In addition, they are in close-proximity to the hot exhaust system, so any lubrication/rust protection that is applied soon burns off (adding an unpleasant aroma to the cabin air in the process). Once these valves start to rust (and they will) then there’s a chance that they’ll seize up, thus jamming the heater on or off (or partway between). The only satisfactory solution when this happens is to fit new ones, which cost around £50 each, depending on type. To help avoid your valves from seizing, then, make sure that you regularly alter the heater’s settings from cold to hot, to encourage the valves to operate. A small amount of spray lubricant at service time will help, too, but don’t overdo it or you’ll get a smell in the cabin as the oil burns off. In addition, the valves have springs to help them return to the ‘cold’ position and these springs lose their strength over time, which can lead to the valves not operating over their full range.
Heat exchangers on pre-1983 cars are made from mild-steel so, like any exhaust parts made from this material, they will inevitably rust away over time. The Carrera 3.2’s exchangers, however, were made of much better-quality steel, while the later 964 and 993 cars had long-lasting stainless-steel items. If holes develop in the outer shrouds of the heat exchangers, hot air will simply pass out through the holes rather than continuing through the heating system and into the cabin.
If your heat exchangers have corroded, then the only solution is to renew them – they cannot satisfactorily be repaired. If you’re planning on keeping the car for some time, it’s worth investing in aftermarket stainless-steel exchangers, which should last a lifetime. Prices of mild-steel units start at around £250 each, while stainless-steel versions begin at about £400.
Another possible air (and therefore heat) leak is from the flexible pipes between the heat exchangers and the valves. Because the former are mounted on the engine and the latter on the car body, the link between them has to be flexible. This large-diameter piping rots and splits over time. Also, it’s held in place by steel clips which rust away, causing the pipe to fall off. You should always renew these pipes (which cost about £20 each) and clips as a matter of course when fitting new heat exchangers or valves – stainless-steel clips are a sensible upgrade.
Cars with a thermostatic controller between the seats have an extra potential trouble point. If the heater appears to be on full all the time, first check that the roof-mounted sensor (on pre-1987 cars) is intact and connected – if it isn’t the system will always assume the interior is cold and so set itself to hot all the time.
Next, check that the servo between the seats is moving – you should be able to hear it whirr as you move the rotary knob. If it is doing, but the temperature is not changing, remove the little cover from the side of the unit and check that the rod connecting the servo to the valve has not come off its ball-joint – a simple enough matter to replace.
If the servo is not operating, you’ll need to disassemble the unit and check that all the wires are in place. If they are, it’s possible that the electronic controller has developed a fault and needs replacing. This is an expensive item, so some parsimonious owners choose instead to retrofit the simple lever system from an earlier 911. As a short-term measure, you can alter the valves’ position by pushing the control rod manually through the access hole in the side of the unit.
Note that early versions of this automatic system also had a red-handled lever to act as an over-ride in the event of the thermostat failing. This should never be operated at any other time – doing so can break the internal linkage from the servo.
When it comes to 964 and 993 cars, things get rather more complicated. As with earlier 911s, the heat exchangers and ducting are still the first things to check if a fault occurs, although the former are stainless-steel and protected by an engine undertray, so should be pretty much maintenance-free.
As regards the rest of the system, the various sensors, servos and fans make it difficult to diagnose faults without an in-depth knowledge of the various components (some of which are very inaccessible), and a compatible Bosch diagnostic tester. There are, however, some simple checks you can make yourself.
First, if the system isn’t maintaining a constant (well, fairly constant – it’s never brilliant) temperature, it could be that the sensor built into the control unit is dirty. Use a pair of Blaupunkt-type radio removal tools to take out the control unit from the dash. At the rear you’ll see a tiny fan unit projecting out. Unscrew and remove this to expose the temperature sensor inside the main unit. Gently blow any fluff or dirt away from this, and at the same time check that the little grille on the face of the control unit is clear.
Inconsistent temperatures, and heat not emitting from certain outlets (screen, footwells, dash) suggest that one or more fans and/or valves are not operating. Although it’s very hard to access these, it’s worth just checking certain fuses haven’t blown; namely, those for the rear blower fan (in engine compartment fusebox) and forward blower fan (in luggage compartment fusebox).
A detailed diagnosis of the system may indicate that the control unit has failed (and such a failure can be caused by a non-functioning servo elsewhere in the system). If this is the case, you need to ensure that you get the correct replacement for your car; different units were fitted to early and late 964, 993s, left-hand and right-hand-drive cars, and cars with air-conditioning. Check the part number of the rear of the box.
Finally, on all air-cooled 911s, unpleasant smells emitting from the heater are not uncommon. These can be caused by a rusty exhaust causing noxious fumes to enter the heat exchangers, although if just the outer shroud of an exchanger is rusty this will not lead to exhaust gases entering the system.
More common is a smell of burned oil, caused by oil dripping from the engine onto the heat exchangers. The only solution is to find the source of the leak and repair it. Remember, too, that lubricating the heater valves in front of the heat exchangers can lead to an oily smell as the lubricant heats up.
We always enjoy seeing Porsche 996 Turbos in the workshop – they’re great cars and a pleasure to work on.
This one was in for a common problem – corrosion of the front-mounted air-conditioning condensers and coolant radiators. We see this a lot on 996s, 997s, Boxsters and Caymans.
The condensers and radiators are mounted inside the front bumper and dead leaves and other rubbish get caught up around them. This then attracts and holds moisture which, in turn, leads to the mild-steel radiators corroding and, in time, the air-con gas or coolant will leak out.
So, the moral is to ensure that you regularly clean out these areas or, even better, invest in some mesh grilles to stop leaves entering through the front intakes.
We always check these areas as a matter of course when one of these cars comes in. Oh, and in this case, while the front bumper was off we were able to fix a non-functioning horn!
Buying a Porsche should be an exciting event. Get it wrong, though, and you could end up with an expensive lemon.
That may be because you don’t know what you’re looking for, or perhaps you simply get swept up in the emotion of the purchase and don’t look at the car rationally.
It’s essential, therefore, to have any prospective purchase examined by someone who knows Porsches inside out.
AW Motorsport offers Porsche pre-purchase inspections at its West Sussex headquarters, close to the Hampshire border and within close reach of the A27, A27 and A3.
Undertaking pre-purchase inspections in the workshop is the best way to examine a Porsche as we can get it up on our ramps to analyse the underside, engine and suspension, plus we have access to our specialist test equipment.
Please get in touch for more details about our Porsche pre-purchase inspection service.
We often get asked about Porsche N-rated tyres – what are they and do you need them on your Porsche?
Basically, an N-rated tyres is one that has been specifically approved for use on a Porsche. Most major tyre manufacturers have been producing N-rated tyres since the 1980s for Porsches.
It all started with the Porsche 964 which, at the time, was one of the few German cars not limited to 150mph. So Porsche worked with tyre companies to develop tyres that would, not only cope with high speeds (the 964 was capable of 162mph) but would also complement the car’s handling and general ‘feel’ – something which is key to a Porsche’s characteristics.
These tyres were marked with an ‘N’ for ‘Norm’, the German word for standard. Today, Bridgestone, Michelin, Pirelli and Continental are the main makers of N-rated tyres, with Dunlop, Fulda and Goodyear also offer N-rated tyres for older cars.
Contrary to popular belief, you don’t have to fit N-rated tyres to your Porsche – it won’t invalidate your insurance policy, and any good brand of tyre of the correct size and speed rating will be perfectly safe. However, seeing that N-rated tyres don’t generally cost any more than the equivalent non N-rated version, there is no reason not to choose the correct N-rated tyres for your Porsche. It’s what Porsche designed the car to used with, after all.
We love this video of the new Porsche 911 50th Anniversary.